Evolutionary trends of carbapenem-resistant and susceptible Acinetobacter baumannii isolates in a major tertiary care setting from North India

Infect Genet Evol. 2023 Dec 18:105542. doi: 10.1016/j.meegid.2023.105542. Online ahead of print.ABSTRACTEmergence of carbapenem-resistant A. baumannii (CRAB) is a global, ongoing healthcare concern. CRAB is among the topmost priority pathogens, with various studies focusing on its global population structure and resistant allelic profiles. However, carbapenem-susceptible A. baumannii (CSAB) strains are often overlooked due to their sensitivity to beta-lactams, which can provide important insights into origin of CRAB lineages and strains. In the present study, we report genomic investigation of CRAB and CSAB coexisting in Indian hospital setting. MLST based population structure and phylogenomics suggest they mainly follow distinct evolutionary routes forming two phylogroups. PG-I exclusively for a successful clone (ST2) of CRAB and PG-II comprises diversified CSAB isolates except PG3373, which is CRAB. Additionally, there are few CRAB isolates not belonging to PG-I and sharing clonal relationship with CSAB isolates indicating role of genome plasticity towards extensive drug resistance in the nosocomial environment. Further, genealogical analysis depicts prominent role of recombination in emergence and evolution of a major CRAB lineage. Further, CRAB isolates are enriched in resistomes as compared to CSAB isolates, which were encoded on the genomic island. Such comparative genomic insights will aid in our understanding and localized management of rapidly evolving pandrug resist...
Source: Infection, Genetics and Evolution - Category: Genetics & Stem Cells Authors: Source Type: research